A.one must hear or hearken to, c. gen. pers., E.IA 1010, X.Smp.3.9, etc. (also in pl. ἀκουστέα, Hdt.3.61; “τῶν κρατούντων ἐστὶ πάντ᾽ ἀκουστέα” S.El.340): c. acc. rei, Pl.R.386a: abs., S.OT 1170.
b. one must understand, “τι διττῶς” Str.9.5.12, cf. Gal. 15.484, Olymp.in Mete.337.14; one must interpret, “ὀνείρους” Artem. 1.3.